Pump



Nov. 21, 1961 w. E. DAVIS, JR, ET AL 3,009,422

PUMP

Filed April 25, 1957 4 Sheets-Sheet 1 S I. I! I ll L II i J1| H 1 if -fID n &

w/zz/wv f. $25 372 A TTOF/Vf) 4 Sheets-Sheet 2 PUMP W. E. DAVIS, JR., ETAL Nov. 21, 1961 Filed April 25, 1957 Nov. 21, 19 1 w. E. DAVIS, JR,ETAL 3,009,422

PUMP

Filed April 25, 1957 4 Sheets-Sheet 3 w/zu/w z Ygwm/e 5401 46769771695Nov. 21, 1961 w. E. DAVIS, JR., ET AL 3,009,422

PUMP

Filed April 25, 1957 4 Sheets-Sheet 4 I 1 I II TIE-5 gwfaaw UnitedStates Patent 3,009,422 PUMP William E. Davis, Jr., Eau Gallic, Fla.,and Paul D. *Crothers, Hamilton, Ohio, assignors to The BendixCorporation, a corporation of Delaware Filed Apr. 25, 1957, Ser. No.655,092 2 Claims. (Cl. 103-162) The present invention relates to fluidpumps and more particularly to variable volume fluid pumps of the wobbleor swash plate type.

It is an object of the present invention to provide for a fluid pump arelatively light weight and compact wobble plate and control thereforconstructed to facilitate, manufacture and being reliable in operation.

Other objects and advantages of the invention will become readilyapparent from the following detailed description taken in connectionwith the appended drawings in Which:

FIGURE 1 is a plan view of a pump embodying the present invention;

FIGURE 2 is a sectional View taken along line 2-2 of FIGURE 1;

FIGURE 3 is an exploded view of a wobble plate and its bearing supports;

FIGURE 4 is an end view of the pump shown in FIG- URE 1 viewed from theright of the figure;

FIGURE 5 is a sectional view taken along lines 5-5 of FIGURE 4; and

FIGURE 6 is a sectional view taken along lines 6-6 of FIGURE 1.

Referring now to the drawings numeral 10 designates a housing having abolted-on end portion 12 provided With a fluid inlet 14 and a fluidoutlet 16. A rotor 18 is mounted in the housing and is provided with atubular extension 19 having an operative connection with a drive shaftv20 which is adapted to be driven by suitable means not shown. The rotor18 is provided with a plurality of angular-1y disposed cylinders 22 inwhich are reciprocably mounted plungers 24. The plungers 24 are roundedat one end to receive shoes 26 which bear against the arcuate front face28 of Wobble plate 30. A pair of convex bearing members or trunnions 32and 34 are formed on the wobble plate 30 and extend rearwardly therefromin planes substantially parallel to a plane through the axis of rotationof rotor 18. Trunnions 32 and 34 are diametrically opposed on oppositesides of the drive shaft 20 on a transverse axis through the wobbleplate 30 and are received in pillow blocks or concave bearing members 36and 38 respectively which are respectively mounted in cavities 40 and 42formed in the housing 10. Each pillow block 36 and 38 is formed with twobearing surfaces at right angles to each other, as best shown in FIGURE3.

Wobble plate 30 is urged toward its maximum pumping stroke position by apiston or movable wall 44; and is urged toward its minimum or no strokeposition by a piston or movable wall 46 disposed on the opposite side ofthe trunnion axis from the piston 44.

Piston 44 is reciprocably mounted in a plug 48 which forms one wall of achamber 50. A conduit 52 connects chamber 50 with the outlet 16 wherebypiston 44 is rendered responsive to pump outlet or discharge pressure. Aspring or resilient member 54 reacts between the plug 48 and a retainer56 on the piston 44 to urge the piston into engagement with the wobbleplate so as to position the plate 30 in pumping position when the pumpis started and before the outlet pressure has built up sufliciently tomove piston 44.

Piston 46 is reciprocably mounted in a sealing member 58 located in achamber '60; and is responsive to the pressure in chamber 60. Chamber 60is alternately connected 3,009,422 Patented Nov. 21, 1961 to inlet 14and outlet 16 through conduit 62 and a valve device 64. The area ofpiston 46 subjected to fluid pressure in chamber 60 is larger than thearea of piston 44 subjected to fluid pressure in chamber 50. The areasof pistons 44 and 46 are proportioned so that when both chambers 50 and60 are connected to the outlets 16, piston 46 will be moved againstwobble plate 30 with a force greater than the combined fluid pressureand spring forces acting on piston 44. Thus when chambers 50- and 60 areboth connected to the outlet 16 the wobble plate will be moved towardminimum or no stroke position. When chamber 60 is connected to the inlet14 the combined fluid pressure and spring forces acting on piston 44 aresuflicient to move the wobble plate 30' toward maximum pumping strokeposition. An adjustable abutment 66 in chamber 60 is disposed to engagepiston 46 at a predetermined rotation of wobble plate 30 to determinethe maximum pumping stroke of the plungers 24.

Valve device 64 includes a cylinder 68 formed in the end wall 12 of thepump housing, a valve block 70 is positioned in cylinder 68 and isformed in longitudinal bore 72 intersected by a pair of transverse bores74 and 76. Block 70 is adjustably positioned in cylinder 68 by means ofadjustment nut 78 to place the bores 74 and 76 in respectiveregistration with conduits '62 and 80. Conduit 80 is connected to outlet16. Rotor 18 is formed.

with a cavity or cylinder 82 to accommodate a cup-shaped member 84 whichis bolted to housing 12 in alignment with cylinder 68. A spring 86 ismounted in member 84 between perforated spring retainers 88 and 90.Retainer 88'abuts an end of member 84 and is aligned with a port 92formed in said member to permit passage of fluid from cavity 82 into themember 84. Retainer abuts an end of a valve 94 which is reciprocablymounted in longitudinal bores 72 of valve block 70. A passage 96conmeets the end of valve 94 with an annular groove 98 formed thereon. Asecond groove 100 is formed in valve 9'4 between lands 102 and 104 andis located to register with bore 74 when valve '94 is in neutralposition. Spring 86 is arranged to urge valve 94 to the right as viewedin FIGURE 2 to bring groove 98 in communication with bore 74 wherebychamber 60 is brought into communication with inlet 14 through passage96, port '92, cavity 82, passage 106, pump chamber 108 and conduits 110and 112. In some installations pump chamber 108 is supplied With leakagefluid and need not be connected directly to the inlet in which casechamber 60 is brought into communication with fluid at pump chamberpressure. When the outlet pressure acting on valve 94 has reached apredetermined value, the force of spring 86 will be overcome and thevalve will be moved to the left as viewed in FIGURE 2 to connect chamber60 through conduit 62 and bore 74 with the outlet 16 via bores 72 and 76and conduit 80. An auxiliary cam plate 114 having a central dependingflange 1 16 disposed within the central opening of wobble plate 30 isprovided with a plurality of openings 118 each of which is adapted toreceive a plunger shoe 26. Cam plate 114 is urged into engagement withwobble plate 30 by means of a spring 120 acting through a thrust member.122 which is slidably. mounted on rotor extension 19. Cam plate 114 isprovided to insure retraction of plungers 24, which due to their angulardisposition within the rotor are normally urged towards the retractedposition by centrifugal force.

Although a particular embodiment of my invention has been described, itwill be understood by those skilled in the art that the objects of theinvention may be attained by the use of constructions difierent incertain respects from that disclosed without departing from theunderlying principles of the invention.

We claim:

1. A pump comprising a housing having first and second end walls, aninlet and an outlet in said housing, a rotor in said housing, aplurality of angularly disposed cylinders formed in said rotor, aplunger in each of said cylinders, 21 one piece wobble plate in saidhousing having a front face formed to engage said plungers, a pair ofdiametrically opposed convex trunnion members formed on the rear side ofsaid wobble plate and extending rearwardly therefrom substantiallyparallel to the axis of rotation of said rotor, a pair of concavebearing members formed in said first end wall to respectively receivesaid trunnion members, means defining a pair of diametrically opposedchambers in said first end wall, said chambers being spacedequidistantly between said bearing members, a pair of pistonsrespectively mounted in said chambers and formed to directly engage saidone piece wobble plate substantially opposite the circumference definingthe points of engagement of said plungers with said wobble plate, meansdefining a cavity in said rotor symmetrically disposed about the axis ofrotation of said rotor, a cylinder formed in said second end walladapted to register with said cavity, a valve housing mounted in saidcylinder and adapted to project into said cavity, a conduit connectingsaid valve housing to one of said chambers, a valve in said valvehousing adapted to alternatively connect said conduit to said inlet andoutlet, and a passage adapted to connect the other of said chambers withsaid outlet.

2. A pump comprising a housing having an end wall, an inlet and anoutlet in said housing, a rotor in said housing, a plurality ofangularly disposed cylinders formed in said rotor, a plunger in each ofsaid cylinders, a one piece wobble plate in said housing having a frontface formed to engage said plungers, a pair of diametrically opposedconvex trunnion members formed on the rear side of said wobble plate andextending rearwardly therefrom substantially parallel to the axis ofrotation of said rotor, a pair of pillow blocks mounted in said end wallof said housing to receive said trunnions, at least one of said pillowblocks having two trunnion engaged bearing surfaces at substantially aright angle, means defining a pair of diametrically opposed chambers insaid end wall, said chambers being spaced equidistantly between saidpillow blocks, a pair of pistons respectively mounted in said chambersand formed to directly engage said one piece wobble plate substantiallyopposite the circumference defining the points of engagement of saidplungers with said wobble plate, conduit means for alternativelyconnecting one of said chambers to said inlet and outlet and springmeans in the other of said chambers urging the piston mounted thereininto engagement with said wobble plate.

References Cited in the file of this patent UNITED STATES PATENTS2,453,538 Rauch Nov. 9, 1948 2,455,062 Ifield Nov. 30, 1948 2,484,337Ferris Oct. 11, 1949 2,502,546 Adams Apr. 4, 1950 2,513,758 Talbot July4, 1950 2,543,624 Gabriel Feb. 27, 1951 2,554,047 Moon May 22, 19512,601,830 Berlyn et a1 July 1, 1952 2,604,048 Wahlmark July 22, 19522,661,701 Ferris Dec. 8, 1953 2,749,844 Weisenbach et a1 June 12, 19562,826,922 Wiggermann Mar. 18, 1958 2,845,876 Keel Aug. 5, 1958 FOREIGNPATENTS 580,177 Great Britain Aug. 29, 1946

